Wednesday, December 18, 2013

Gmail Users: Google Makes Your Data More Secure, Owns a Bit More of Your Life

The lovely people at Google have just quietly released a new feature. Google's mail client now automatically shows images from all senders.

Apparently, this is safe now - because all images you see in gmail will be proxied through google's own servers. Now we don't have to worry about viruses and malware in images. Well, we didn't often worry about those in the past - images containing viruses are most often a hoax, the odd PoC, and of course there are some targeted attacks at poorly written image libraries which would form the basis for a driveby. These concerns, and their validity or otherwise, aren't the real reason we turned off images are they?

No, we turned off images because we wanted to make the trade off between marketing people tracking us, and seeing the image. If the image was going to be useful, or worth seeing, we'd load images. If not, it was probably a "web bug" use to track opens and forwards by canny marketing types.

So, now you know that every image in your gmail is being definitely tracked by canny marketing types - except it is those at Google, rather than the guys who sent the email who are getting the full picture. Bear in mind also, that this is implicitly an HTTPS man-in-the-middle attack. This means that if an image was previously sent securely end-to-end between the email sender and you, it has now resided in the clear somewhere on Google's servers. Of course it's still encrypted in transit - but at some point that image stopped being secure, its origin stopped being verifiable in the same way, and Google served it to you fresh.

I know that Google already know what you are doing with your gmail, but this is one more fragment of your web browsing that's now hitting their servers before it hits the origin.

Yes, I fully appreciate the irony that this blog post resides on Google's infrastructure. They already know what I had for breakfast anyway.

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